NASA’s experimental X-59 aircraft marked a major milestone Friday, June 5, when it flew faster than the speed of sound for the first time, setting the stage for demonstrating its quiet supersonic capabilities later this year.
NASA test pilot Jim “Clue” Less took off and landed at Edwards Air Force Base in California, reaching a top speed of approximately Mach 1.1 (713 mph) and altitude of 43,400 feet. The X-59’s flight began at 11:08 a.m. PDT and lasted 81 minutes, with the team focusing on flying qualities at both subsonic and then supersonic speeds.
jared isaacman
NASA Administrator
”X-59 is getting ready for its quiet supersonic debut. Since the aircraft’s first flight on Oct. 28, 2025, the team has made tremendous progress, flying 16 times in the last 90 days and getting into a steady test rhythm. In the coming days, we expect to take the next step and push to Mach 1.4,” said NASA Administrator Jared Isaacman “I’m grateful to the NASA team and Lockheed Martin Skunk Works for their help getting us to this point, and I hope this is the first of many collaborations as we rebuild NASA’s X-plane portfolio.”
The X-59 is designed to fly at supersonic speeds while creating only a quiet thump instead of a loud sonic boom. For this flight, a NASA F‑15 chase plane flew nearby to monitor the X‑59. The loud sonic booms from the F-15 obscured any sound made by the X-59.
“The X-59’s first supersonic flight is a testament to America’s enduring leadership in science, engineering, and aerospace innovation,” said Michael Kratsios, Assistant to the President for Science and Technology and Director of the Office of Science and Technology Policy. “This achievement comes as the Trump Administration continues work to unleash supersonic flight and enable American ingenuity.”
This first supersonic flight is a significant milestone, but an event even more critical to the mission is upcoming. In just days, the aircraft is expected to make its first “mission conditions” flight, reaching a cruising speed of Mach 1.4 (925 mph) and altitude of approximately 55,000 feet. The X-59 also will be accompanied by a chase plane for this flight.
This speed and altitude are the base conditions for the X-59 when it will eventually fly over several U.S. communities enabling NASA to gather data about how people may perceive its quiet thump. NASA will share this data with U.S. and international regulators to help establish new data-driven noise standards to enable a future viable market for supersonic commercial flight over land.
For the last several months, the X-59 has been participating in an ongoing series of flights where the plane has been flying at a wide range of speeds and altitudes – a process known as envelope expansion. These tests are the first phase of the X-59’s flight testing. They are focused on performance and involve chase plane monitoring. When the aircraft completes this phase it will enter another, focused on its sound profile in order to verify its quiet thump capability.
The X-59 is the centerpiece of NASA’s Quesst mission, which aims to demonstrate quiet supersonic flight and help enable commercial supersonic flight over land worldwide. These advancements will help travelers reach their preferred destinations faster, spending less time in the air.
Through Quesst’s development of the X-59, NASA also will deliver design tools and technology for quiet supersonic airliners that will achieve the high speeds desired by commercial operators without disturbing people on the ground. NASA will validate design tools through ground and flight testing, providing U.S. aircraft manufacturers the ability to explore new quiet supersonic concepts, and provide them with confidence that their resulting designs will meet quiet flight requirements.
